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Re: [PATCH 0/6] Yet another approach to handling empty snapshots

From
Jeff King <peff@peff.net>
Date
Jan 24, 2018, 20:38 UTC
Message-ID
<20180124203806.GD7773@sigill.intra.peff.net>
In-Reply-To
<cover.1516791909.git.mhagger@alum.mit.edu>
On Wed, Jan 24, 2018 at 12:14:10PM +0100, Michael Haggerty wrote:
Show 11 quoted lines
> This patch series fixes the handling of empty packed-refs snapshots
> (i.e., those with `snapshot->buf` and friends equal to `NULL`), partly
> by changing `snapshot` to store a pointer to the start of the
> post-header `packed-refs` content instead of `header_len`. It makes a
> couple of other improvements as well.
> 
> I'm not sure whether I like this approach better than the alternative
> of always setting `snapshot->buf` to a non-NULL value, by allocating a
> length-1 bit of RAM if necessary. The latter is less intrusive, though
> even if that approach is taken, I think patches 01, 02, and 04 from
> this patch series would be worthwhile improvements.

This looks good to me. I agree that 1, 2, and 4 are improvements regardless (but 4 as it is now depends on 3, right?).

I don't have a strong opinion between this series and the other options presented. It's probably not worth agonizing over, so we should pick one and move on.

-Peff
Previous: Michael HaggertyNext: Junio C Hamano
Message 19 of 33 in “packed_ref_cache: don't use mmap() for small files”
  1. packed_ref_cache: don't use mmap() for small filesKim Gybels, Jan 13, 2018
  2. Johannes SchindelinJan 13, 2018
  3. packed_ref_cache: don't use mmap() for small filesKim Gybels, Jan 14, 2018
  4. 0/3 Supplements to "packed_ref_cache: don't use mmap() for small files"Michael Haggerty, Jan 15, 2018
  5. Johannes SchindelinJan 17, 2018
  6. Junio C HamanoJan 17, 2018
  7. 1/3 SQUASH? Mention that `snapshot::buf` can be NULL for empty filesMichael Haggerty, Jan 15, 2018
  8. 2/3 create_snapshot(): exit early if the file was emptyMichael Haggerty, Jan 15, 2018
  9. 3/3 find_reference_location(): don't invoke if `snapshot->buf` is NULLMichael Haggerty, Jan 15, 2018
  10. Jeff KingJan 15, 2018
  11. Kim GybelsJan 15, 2018
  12. Jeff KingJan 15, 2018
  13. packed_ref_cache: don't use mmap() for small filesKim Gybels, Jan 16, 2018
  14. Jeff KingJan 17, 2018
  15. Michael HaggertyJan 21, 2018
  16. Junio C HamanoJan 22, 2018
  17. Michael HaggertyJan 24, 2018
  18. 0/6 Yet another approach to handling empty snapshotsMichael Haggerty, Jan 24, 2018
  19. Jeff KingJan 24, 2018
  20. Junio C HamanoJan 24, 2018
  21. Johannes SchindelinFeb 15, 2018
  22. 1/6 struct snapshot: store `start` rather than `header_len`Michael Haggerty, Jan 24, 2018
  23. Jeff KingJan 24, 2018
  24. 3/6 find_reference_location(): make function safe for empty snapshotsMichael Haggerty, Jan 24, 2018
  25. Jeff KingJan 24, 2018
  26. Junio C HamanoJan 24, 2018
  27. Jeff KingJan 24, 2018
  28. 2/6 create_snapshot(): use `xmemdupz()` rather than a strbufMichael Haggerty, Jan 24, 2018
  29. 5/6 load_contents(): don't try to mmap an empty fileMichael Haggerty, Jan 24, 2018
  30. 4/6 packed_ref_iterator_begin(): make optimization more generalMichael Haggerty, Jan 24, 2018
  31. Jeff KingJan 24, 2018
  32. 6/6 packed_ref_cache: don't use mmap() for small filesMichael Haggerty, Jan 24, 2018
  33. Junio C HamanoJan 24, 2018

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